The objectives of this project are five fold: 1. To analyze the structure of retinal receptor outer segments of the frog retina. In particular, the objective is to develop procedures employing electron microscopy and immunohistochemistry which will serve to localize functional subunits (visual pigments) within the membranes of outer segments. Peroxidase labeled antibodies will be used to study the distribution of membrane antigens along the surface of these biological membranes by negative staining and thin-section technique for electron microscopy. 2. To localize by immunohistochemistry rhodopsin within the iris of the frog eye. 3. To develop methods for the isolation of sarcolema from frog cardiac muscle. Identification of the membrane preparation will be done by analysis for enzymic markers and Immunohistochemical procedures employing the peroxidase labeled antibody. Finally, a chemical analysis of the proteins and lipids of the membrane preparation will be performed. 4. To determine the effect of antisarcolemmal antibody on the action potential and conduction velocity in the giant axons of the earthworm. 5. To analyze the structural changes of paramyosin-containing thick filaments in sarcomeres of Limulus striated mus de during shortening. Light diffraction techniques coupled with electron microsocpy will be used.